The U.S. Federal Trade Commission is reportedly gearing up to announce a formal antitrust investigation into Google's business practices, according to sources speaking to the Reuters news agency.

The U.S. government's trade regulator may be preparing the investigation to start as soon as November or December, as European regulators continue to simultaneously probe the search giant for allegedly abusing its dominant position in the search market.

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Reuters cited four FTC commissioners who have become "convinced" that after a year of investigating the firm's dominance in the market hurts its competitors and rivals. One commissioner however remains "skeptical," citing three anonymous sources.

Rival firms claim that Google serves up its own products and services ahead of its rivals in search queries. Schmidt said that its own services are subject to the "same search ranking algorithm process as all organic search results."

But the FTC has clearly found something -- we presume it relates to Google's search and advertising business, but will find out when the FTC announces something, expected in the coming days or weeks -- that the trade watchdog believes the search giant falls foul of U.S. antitrust law.

On the other side of the pond, the European Commission continues to focus on its own investigation into the search giant, which remains in relative stasis since early this year.

EU Competition Commissioner Joaquin Almunia said last month that the negotiations continue but are "not there yet." He added that if Google does not offer "effective solutions" to the complaints: "I will be obliged to continue with our formal proceedings," he added.

Google could face a maximum fine of up to 10 percent of their global turnover, amounting to €2.9 billion ($3.8bn) based on the firm's 2011 global revenue.

Typically, though the U.S. FTC and the European antitrust authorities work independently and separately, they often work together on matters on transatlantic matters. It's not uncommon therefore, for example, for an European and U.S. antitrust matter -- whether a probe or clearing two merging companies -- to be announced at the same time.

Questions were left with Google but did not respond at the time of publication. The FTC did notrespond outside U.S. business hours.